in_bulk not working for distinct fields

[Wolph]

The in_bulk queryset function currently checks for the pk field or for unique fields. But if you do a queryset.distinct(field) that field is also unique for that queryset so it should be usable for an in_bulk.

I believe the fix would be as easy as patching these lines: ​https://github.com/django/django/blob/41725602afebe2ddb018b99afe134384cc3bf69e/django/db/models/query.py#L699-L703

To include and field_name not in self.query.distinct_fields

[Simon Charette]

Feature request makes sense, PR with tests is welcome.

Note that this only works if there's a single field being distinct on; distinct('foo', 'bar').in_bulk(field_name='foo') should not work. In other words the logic should be self.query.distinct_fields == (field_name,) and not check for containment as suggested above.

[Kaustubh]

I'd like to work on this

[Wolph]

I was planning to create a PR over the weekend, but you're more than welcome to give it a try :)

[Kaustubh]

Replying to Wolph:

I was planning to create a PR over the weekend, but you're more than welcome to give it a try :)

Thanks, I'll inform you if I get stuck (I'm a newcomer to open source)

[Kaustubh]

Linked PR : ​https://github.com/django/django/pull/13338

[Mariusz Felisiak <felisiak.mariusz@…>]

In b9be11d4:

Fixed #31918 -- Allowed QuerySet.in_bulk() to fetch on a single distinct field.